These surveys were based on personal interviews completed with 12,571 respondents 15-44 years of age and comprising 7,643 females and 4,928 males. The main purpose of the NSFG surveys has been to provide reliable national data on marriage, divorce, contraception, infertility, and the health of women and infants in the United States. The survey contains key religion variables that may relate to these goals. Cycle 6 expands upon this mission by interviewing male respondents for the first time.

The female respondent file uses each female respondent as the unit of analysis and contains detailed fertility histories, social characteristics, and personal histories of each respondent (including religion variables), as well as selected characteristics of each respondent's pregnancy history. The recodes were created to simpify analyses, and are provided for key variables in virtually every topic.

Using the common identification number (CASEID), and the pregnancy number (PREGORDR), the interval and respondent files can be merged to produce a file containing both respondent information and pregnancy information. The resulting file can be either respondent-based (up to 12,571 records) or interval-based (up to 13,593 records).